Electric furnace.



PATBNTED FEB. 13, 1906.

J. E. OBER. ELECTRIC FURNACE.

APPLICATION FILED JULY 15, 1904.

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Witnesses:

JULIUS E. OBER, OF'SCHENECTADY,

NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY. A CORPORATION OF NEV YORK.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Feb. 13, 1906.

Application filed July 15, 1904.' Serial No. 216,875.

To all whom it may concern-.-

Be it known that I, JULrUs E. Omani, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

My present invention relates to electric furnaces, and more particularly to that class of electric furnaces known as carbon-tube furnaces, in which a tubular member made out of suit-able conducting material, such as carbon, is heated by the passage through it of an electric current. The objects. to be heated by the furnace are placed in the bore of the tubular member.

When furnaces of this character are operated, the tubular member when heated rapidly deteriorates unless steps are taken to irevent its oxidation. Heretofore the tubular member in furnaces of this character when made of carbon has frequently been acked in coke to prevent oxidation. I have ibund, however, that tubular members made out of carbon surrounded by coke when operated at high temperatures deteriorate rapidly from some cause, the exact nature of which I am unable to state with certainty.

sults it is desirable that the layer 5 of tita- From my observations it seems probable that this deterioration is caused by or at least assisted by the presence of impurities, such as My observations also silica, in the coke. lead me to believe that a. portion of the current is shunted from the tubular member tively thin layer of titanium carbid, and then surround it in turn by a. packing of coke.

The packin of coke serves to protect the titanium carbit from oxidation, and also serves as a refractory shield to prevent the dissipation of heat from the furnace.

In the accompanying drawings, of which Figure 1 is an elevation and Fig. 2 a sectional ilevation, I have illustrated a portion of an electric furnace embodying my invention.

In the drawings, 1 represents somewhatmassive and pieces, which may be formed of l carbon, raphite, or the like, and 2 represents the tubu ar member of the furnace. The tubular member 2 in the construction shown comprises two cylindrical portions 3 and an intermediate concentric c lindrical portion 4, I the external diameter 0' which is less than that of the end portion. A layer 5 of titanium carbid surrounds the portions 4 of the member 2. The outer surfaces of the layer 5 may be flush with the outer surfaces of the end portions 3. The inner ends of the end DIGIHhG-LS l are socket-ed at 6 to receive most of the end portions 3, as shown. A cylinl portions of the end member 1 shown in the drawings and the member? and its roteetive layer 5 are embedded in a mass 0 coke 8. Suitable connections (not shown) are provided for supplying suitable current to the end members 1. The means for supplying current to the end membersv 1 and for protecting and supportingthem are not shown in the drawings, as they form no part of my present invention.

I have found that to obtain the best renium cal-bid should be substantially uniform in thickness. A uniform layer can be advantageousl y obtained in the following manner: A sheet of material, such as paper, is wrap ed about the enlarged end portions 3. his forms a. cylindrical casing concentric with the portion 4.. but separated therefrom by a space equal to the thickness of the layer 5. The section of this casing is represented in Fig. by the lines marked 9. I then fill the s more between the casing and the portion 4 o the member 2 with titanium carbid in a finelypowdered form. The member) is then surrounded by a )a cking of coke 8.

As soon as t to furnace thus formed'is heated to the working temperature the powdered titanium carbid sinters together to form a shell having considerable mechanical strength The shell or casing, formed of paper or similar material, chars as the furnace heats up. I

The protective layer 5, formed of titanium carbid, is a good conductor of electricity and is non-hygroscopic and is refractory. The titanium-carbid layer 5 is less affected by any electric discharge which may take-place drical passage 7, ordinarily of uniform crossinvention now known to me, it is obvious that it may be used in other forms from that shown in the drawings.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. In an electric furnace, a carbon tube, and a coating therefor formed of titanium carbid.

2. An electric furnace comprising a carbon tube heated by the passage of current through its wall, and a protective shell formed of titanium *arbid.

3. In an electric furnace, at carbon tube, a la yer of titanium carbid surrounding the tube. and a acking of coke surrounding the titaninmear id,

,4. In an electric furnace, a'tubular memln-r formed of conducting material comprising two cylindrical end portions, and intermediate portions of reduced diameter.

5. In an electric furnace, a tubular member comprising two end ortions and an int-eri-nediate portion iofre uc-ed;diameter, and a protective sheath surrounding said reduced portion.

6. In an electric furnace, a tubular member comprising two end ortions and an in termediate portion of re uced diameter, and aprotective sheath surrounding said reduced portion, said protective sheath being formed of titanium carbid.

7. In an electric furnace, a tubular member comprising two'end portions, and a reduced intermediate connect' portion, a packing of refractory non-oifiifizable material formed with a passage in it of a diameter substantially the same as that of the end ortions, and a mass of protective materia located in the space between said refractory material and the reduced intermediate portion of the tubular member.

8. In an electric furnace. a tubular heating member, a sheath therefor of titanium carbid, and a packing of finely-divid ed, heat-resisting materialjsurrounding said sheath.

9. In an electric furnace, a tubular heating member of carbon, and a sheath therefor consisting of a sintered mass of finely-divided titanium carbid.

10. In an electric furnace comprising a carbon tube heated by the ussage of current through it, a protective sheath for the tube formed of titanium carbid, and a mass of coke surrounding said sheath and the carbon tube inclosed thereby.

11. In an electric furnace, a carbon-tube heating member comprising end portions and an intermediate portion of reduced diameter, and a sheath for the reduced portion formed by wrapping naper about the heating member and then filling the space left between the paper and the reduced portion of the heating member with titanium carbid.

12. In an electric furnace, a heating member, and a protective sheath or coating there for formed of non-hygroscopic carbid.

13. In an electric furnace, a heating mem her, and a protective sheath or coating therefor formed of a uon-hygroscopic refractory carbid.

In witness whereof I hereunto set my hand this 12th day of July, 1904.

JULIUS E. OBER.

\Vitnesses:

BENJAMIN B. HULL, HELEN ORrom). 

